uot;MARGIN: 0cm 0cm 0pt" class=MsoNormal>uot;FONT-FAMILY: ’Times New Roman’,’serif’; BACKGROUND: #f4f4f4; COLOR: #242424; FONT-SIZE: 9pt" lang=EN-US>This paper mainly discusses theory of 204Pb correction, sources and measuring method of 204Pb, and effect of 204Pb on the result. The study test indicates that the inaccurate measurement of 204Pb can drift age spots from the concordant line, making the average age higher or lower. In addition, the intensity of the primary beam, uniformity, shape of the beam spot, and raster time may also affect the measurement of common Pb. Due to the low content of 204Pb in most zircon samples, is more beneficial to scan the 204Pb peak at the fractures, the inclusions on high-uranium zircon, or the 204Pb-rich minerals, like feldbar. The peak position of 204Pb is usually slightly offset to the right of the peak center in order to avoid peak interference.uot;FONT-FAMILY: ’Times New Roman’,’serif’" lang=EN-US>uot;urn:schemas-microsoft-com:office:office" />